481 research outputs found

    Infection of cultured and freshwater fishes with monogeneans in Syria

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    During a survey made in 2004 and 2005 in Syrian fish farms of the Orontes valley and on natural water fishes harvested in the Orontes River and in Lake Assad (a water reservoir of the Euphrates River), 145 specimens of fish belonging to 15 fish species were examined for monogenean infections. Eleven monogenean species (8 Dactylogyrus spp., 1 Silurodiscoides sp. and 2 Cychlidogyrus spp.) were found in the gills. Monogeneans infecting farm-cultured fishes were the same as those commonly occurring in cyprinids (Dactylogyrus anchoratus, D. extensus, D. lamellatus) and filapia (Cychlidogyrus tilapiae, C. arthracan thus) cultured in Europe and in tropical countries. Among monogeneans found in fishes of natural waters, typical representatives of the Tigris-Euphrates Basin (Dactylogyrus carassobarbi, D. holciki) and species common in the Holoarctic zoogeographical zone (D. alatus, D. carpathicus, D. distinguendus and Silurodiscoides vistulensis) were equally found

    The 1991 southern hemisphere complex of activity

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    We have investigated the development of a complex of activity which took place in the southern hemisphere of the Sun between July 1991 and April 1992. The whole process culminated with the successive formation of two large active regions with sunspot groups NOAA 6850 (September/October) and NOAA 6891 (October/November 1991), both having complicated magnetic fields, but the former without heavy flare activity. We observed the appearance of the individual active regions as the consequence of the development stage of large-scale magnetic fields in the given area of the solar surface, in connection with their longitudinal and latitudinal distribution. We have studied the dynamics of this development on magnetic synoptic charts, as well as on spectroheliograms taken in the K-line of ionized calcium. Our new observations confirm the regularities found earlier and connection of global and local developments with convection. We think that they could become a tool for solar activity prediction and that they could be used for comparative studies of stellar complexes of activity

    Development of Myxobolus dispar (Myxosporea : Myxobolidae) in an oligochaete alternate host, Tubifex tubifex

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    The development of Myxobolus dispar Thelohan, 1895, a myxosporean parasite of the gills of common carp (Cyprinus carpio L.) was studied in experimentally infected oligochaetes Tubifex tubifex Muller. After infection of uninfected tubificids with mature spores of M. dispar development of actinosporean stages was first observed light microscopically 21 days after initial exposure. In histological sections, early pansporocysts were located in the gut epithelium of experimental oligochaetes, while advanced stages occupied mostly the outer layers of the gut and the coelozoic space. Mature pansporocysts, each containing 8 raabeia spores, appeared 199 days after initial exposure. Following damage of the intestinal wall and rupture of the pansporocysts, free actinosporean stages were found in the gut lumen of the oligochaetes. Actinospores of M. dispar emerged from the worms after 217 days of intra-oligochaete development. They were floating in the water and showed a unique raabeia form. Each raabeia sport had three pyriform polar capsules and a cylindrical-shaped sporoplasm with approximately 32 secondary cells. The spore body joined the three caudal projections without a style. Caudal projections were bifurcated at the end and the two main branches had further small bifurcations. The total length of the raabeia sport was approximately 158 mu m. The prevalence of infection in 240 experimentally infected Tubifex specimens was 99.2%. No infection was found in the control oligochaetes

    POSSIBILITIES FOR CONTROLLING THE CONNECTION BETWEEN WASTEWATER TREATMENT PLANTS AND RECEIVING WATER BODIES

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    With increasing water supply and canalization the quality of the water playing the role of receiver often deteriorates. Among other problems, the not sufficient removal of plant nutrients by the traditional purification technology causes difficulties. Considering that the removal of fertilizers results in a significant increase in the costs of wastewater treatment, it is expedient to keep the extent of removal just at the yet acceptable level of the pollutant. This paper deals with the removal of phosphorus as fertilizer on a transport theoretical basis. As a result, a qualitative connection is established between water quality and water management on the one hand and the operation of the wastewater treatment plant on the other hand

    Development of Thelohanellus hovorkai and Thelohanellus nikolskii (Myxosporea : Myxozoa) in oligochaete alternate hosts

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    The development of Thelohanellus hovorkai, a myxosporean parasite of the connective tissues, and Thelohanellus nikolskii, a fin and scale parasite of common carp (Cyprinus carpio) was studied in experimentally infected oligochaetes Branchiura sowerbyi and Tubifex tubifex, respectively. After infection with mature spores of T. hovorkai, the development of actinosporean stages was first observed light microscopically in the gut of Branchiura sowerbyi 93 days after infection. Free actinospores of T. hovorkai were found in the lumen of the oligochaete's gut 101 days after infection. They were floating in water and showed a typical aurantiactinomyxon form. At 18-22 degrees C, aurantiactinomyxon spores of T. hovorkai emerged from the worms 104 days after infection. The development of T. nikolskii was examined in Tubifex tubifex, from which aurantiactinomyxon spores were released 60 days after infection at 22-24 degrees C. The diameter of spore body was 18.6 mu m and the lenght of caudal processes 29 mu m for T. hovorkai, while 21.1 mu m and 13.4 mu m for T. nikolskii, respectively. The prevalence of aurantiactinomyxon infection in B. sowerbyi for T. hovorkai proved to be 16.7%, while in T. tubifex for T. nikolskii it was 12.5%

    Substance p immunoreactivity exhibits frequent colocalization with kisspeptin and neurokinin B in the human infundibular region.

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    Neurons synthesizing neurokinin B (NKB) and kisspeptin (KP) in the hypothalamic arcuate nucleus represent important upstream regulators of pulsatile gonadotropin-releasing hormone (GnRH) neurosecretion. In search of neuropeptides co-expressed in analogous neurons of the human infundibular nucleus (Inf), we have carried out immunohistochemical studies of the tachykinin peptide Substance P (SP) in autopsy samples from men (21-78 years) and postmenopausal (53-83 years) women. Significantly higher numbers of SP-immunoreactive (IR) neurons and darker labeling were observed in the Inf of postmenopausal women than in age-matched men. Triple-immunofluorescent studies localized SP immunoreactivity to considerable subsets of KP-IR and NKB-IR axons and perikarya in the infundibular region. In postmenopausal women, 25.1% of NKB-IR and 30.6% of KP-IR perikarya contained SP and 16.5% of all immunolabeled cell bodies were triple-labeled. Triple-, double- and single-labeled SP-IR axons innervated densely the portal capillaries of the infundibular stalk. In quadruple-labeled sections, these axons formed occasional contacts with GnRH-IR axons. Presence of SP in NKB and KP neurons increases the functional complexity of the putative pulse generator network. First, it is possible that SP modulates the effects of KP and NKB in axo-somatic and axo-dendritic afferents to GnRH neurons. Intrinsic SP may also affect the activity and/or neuropeptide release of NKB and KP neurons via autocrine/paracrine actions. In the infundibular stalk, SP may influence the KP and NKB secretory output via additional autocrine/paracrine mechanisms or regulate GnRH neurosecretion directly. Finally, possible co-release of SP with KP and NKB into the portal circulation could underlie further actions on adenohypophysial gonadotrophs

    [(CH3)3Si]14Si7O21 - ein neuer cyclischer Kieselsäuretrimethylsilylester

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    Durch Trimethylsilylierung des Bariumchloridsilicates 2BaO - 3BaCl2 - 2SiO2 wurde ein bisher unbekannter Kieselsäuretrimethylsilylester hergestellt, der mit Hilfe der Kapillargaschromatographie, Massenspektroskopie29Si-NMR-Spektroskopie und Dünnschichtchromatographie charakterisiert wurde. Aus den Untersuchungen folgt für den Ester die Konstitution eines Cycloheptakieselsäuretrimethylsilylesters (Tetradecakistrimethylsiloxicycloheptasiloxan) der Formel [(CH3)3Si]14Si7O21. Die Verwendung des Esters als Standardsubstanz wird diskutiert
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